The invention of the present application relates to improvements in joint-sealing apparatus for roadways and is particularly concerned with apparatus of that type for use on bridges, overpasses and the like.
Modern highways including bridges, overpasses and the like are in many cases formed of concrete slabs. Such slabs, as a result of changes in temperature, expand and contract. To prevent buckling or heaving on expansion, gaps must be provided between the slabs. However, such gaps permit entrance of debris such as stones and dirt as well as water. The debris and the water, when the latter is frozen, may interfere with expansion of the concrete slabs and/or cause cracking or chipping of the adjacent concrete surfaces. When, as is frequently the case, the roadway is elevated, for example, on a bridge instead of resting on a stone foundation, the leakage of water through the gaps on objects or people below is also a problem.
On concrete roads supported on the ground surface, the gaps at joints in the roadway are conveniently closed by elongated, resilient, hollow sealing members. Where, however, the roadway is supported in the air, for example on bridges, elevated highways, and the like, there is not only movement of the concrete slabs in a horizontal plane, but also at times, as a result of variation in loading, the slabs move vertically with respect to one another. Sealing of the joint gaps under such conditions is a much more difficult matter. Not only is it desired to seal the gaps from leakage of liquids, primarily water, and accumulation of debris, but also to reduce noise occasioned by traffic passing over the gaps, to protect the edges of the slabs from spalling, and to maintain firm surfaces adjacent the gaps so that vehicle wheels pass easily over the gaps without excessive deformation of the sealing apparatus. Many efforts have been made to satisfactorily seal such gaps. Examples of such efforts are disclosed in U.S. Pat. Nos. 3,850,539 and 3,713,368, but the results are not entirely satisfactory in some types of installations.
It is an object of the present invention to provide sealing apparatus suitable for use in roadway joint-gaps on bridges and the like which not only provides proper sealing of the gap within a considerable range of relative movement of the adjacent concrete slabs, but which also resists deformation by heavy loads and wear by traffic.